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4/18 Graphs



This question involves graphs, which mean you must take a slightly different approach to reading carefully. Skimming over the images to get to the words is extremely tempting, but the labels and trends easily visible on graphs can be instrumental in solving the problem.


graphic

Look at the graph before you read the instructions in the question. First, the title is "PURCHASES AT A GROCERY STORE," so you know what the dots represent. Next, look at the axes. The X-axis displays the number of items by multiples of 5, and the Y-axis displays the total cost of each purchase. Finally, look at the content of the graph. This scatterplot shows that, in general, the more items people buy, the greater the cost of their purchase. Some people are able to get more groceries for their money, but not many people spend huge amounts of money on few items.

Now that you know what the graph shows, look at the question.

The scatterplot above shows the number of items purchased at a grocery store by 28 customers and the total cost of each purchase. How many of these 28 customers bought more than 10 items and spent less than $20?

The bottom line in this question has two parts: more than 10 and less than $20. Look at the scatterplot to find an answer that fills both requirements.


First, focus on more than 10 items. The 10 on the X-axis indicates those who bought ten items or more. Visually draw a line upward from there. Every dot to the right of the line bought more than ten items. Keep in mind that since the problem specifies more than, the dots on the 10 line do not qualify.

Next, focus on less than $20. Look at the Y-axis to find the $20 line. Extend that line to the right until it intersects the 10-item line. Points below this line represent purchases that totaled less than $20.

Now look at the lower-right quadrant of the grid you just created. The points in this area of the scatterplot represent purchases of more than 10 items that cost less than $20. Count them, and you have your answer!

A) Four

B) Five

C) Six

D) Seven

E) Eight

The answer is A.


On sat.collegeboard.org, 54% of responses were correct.


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